Rotary cooler and dryer



G. HALLDoRssoN 2,857,684

ROTARY cocu-:R AND DRYER Oct. 28, 1958 2 Sheets-Sheet 1 Filed April 12, 1956 INVENTOR HA LLDORSSON ATTORNEY GISLI BY @fz/mmm,

Oct. 28, 1958 e. HALLDoRssoN ROTARY cooLER AND DRYER 2 Sheets-Sheet 2 Filed April 12, 1956 INVENTOR HALLpoRSsoN.

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U s G ATTORNEYS ROTARY COOLER AND DRYER Gisli Halldorsson, Baltimore, Md., assignor to Edward Renneburg & Sons Company, Baltimore, Md., a corporation of Delaware Application April 12, 1956, Serial N0. 577,845

15 Claims. (Cl. 34-66) This invention relates to an improved countercurrent rotary cooler and dryer which may also be used as a mixer or reactor for various types of chemical compounds and specifically superphosphate fertilizers.

The invention contemplates broadly the provision of a rotary drum dryer provided at its discharge, air intake extremity with a cylindrical neck section of reduced diameter through which extends a valved unloading pipe structure, the neck section extending into an inwardly enlarging conical or hemispherical section extending into an enlarged diameter retention and processing section of extended length, which again reduces into a decreasing conical or hemispherical section and thence to a reduced diameter cylindrical section into which the material feed extends. This reduced diameter feed section is sealed at its extremity and is provided with a telescoping internal exhaust duct which passes through the sealing plate and into closed communication with an enlarged industrial fan which draws the air through the entire structure and forces it upwardly through a conduit to a cyclone separator of conventional form, which is not shown. The

fan may be placed on the clean suction side of the cyclone separator. The entire rotating drum structure is mounted y at its restricted extremities on suitable rollers for apfpropriate rotation, motive power for the rotation of the drum being provided through a ring gear applied about i. the outer periphery of the reduced feed section of the drum The primary purpose of the improved cooler and dryer drum structure is to create a unit which will permit a larger hold-up by time and by percentage of unit volume and a greater output capacity per cubic foot of volume and of unit weight than is now possible with similar known units. The unit is designed to be usable as a cooler, dryer or as a combination dryer and cooler and is designed to be capable in certain applications of performing both operations simultaneously. Further, due to its novel design the unit requires less installation space for a desired capacity than was previously required.

The invention also contemplates a unit which is completely free from dust losses, eliminating the loss of fine vmaterial at the feed end thereof which creates wear on 'the seal and a nuisance. problem and results in the loss of a considerable percentage of these fine particles.

It is therefore a primary object of this invention to fevolve a countercurrent cooler and dryer unit which for :a certain capacity requires less space for installation and which is of considerably smaller size than presently Lknown units.

It is a further object of this invention to provide such :a unit with improved unloading means at its discharge extremity whereby a certain material level can be maintained in the unit corresponding to the hold-up or processing time desired for a certain feed rate.

Another object of this invention s to provide an improved adjustable internal exhaust duct at the feed extremity of the unit to eliminate dust losses and to con- United States Hatent 'l Patented Get. 2:8, 1858 trol the discharge of fine particles of the material being processed.

lt is a further object of this invention to provide improved material feed means at the feed extremity of the unit.

Another object of the invention is to provide improved spirally arranged flights in the retention section of the dryer whereby the material being processed is assisted in moving through the dryer drum counter to the how of processing air therethrough.

Other and further objects of this invention will become apparent as this specification proceeds.

Referring to the drawings,

Fig. 1 is a side view, partially broken away and in section, showing the complete cooler and dryer drum unit;

Fig. 2 is. a cross sectional view taken on line 2 2 of Fig. l taken at the feed extremity of the unit; and

Fig. 3 is an end view of the unit taken at the discharge end thereof.

In the drawings, 5 indicates a rotary dryer drum which comprises a restricted air entry neck 6 of reduced diameter and length which extends into an outwardly diverging conical section 7, extending into retention and processing section 8 of enlarged diameter and length. Retention section 8 extends into converging conical section 9 and thence into feed section l@ of reduceddiameter.

Discharge section 6 is provided about its outer central periphery with a tire 11 which seats on paired rollers 12 appropriately supported on a xed base 13. Feed section 10 is provided about its outer periphery with a tire 14 which rotatably registers with paired rollers 15 appropriately mounted on fixed base 16, this drive band and roller arrangement rotatably mounting the entire cooler and dryer drum structure.

Feed section 10 is also provided about its outer periphery with a ring gear 17 which appropriately registers with a suitable drive gear from a suitable source of power for rotating the entire unit.

Feed section 10 is provided at its outer periphery with a rectangular shoulder 18 which defines a central, circular orific-e therein through which are passed the lower extremity of the material feed chute 19 and extensible internal exhaust duct 20, which will be more fully discussed further on in this specification.

Feed section 1i) is provided about its inner periphery with a spiral feed flight 21 designed to shower and feed the material entering from material feed chute 19 concurrently with the air into conical section 9 and then into retention section 8 of the drum, counter to the flow of airtherethrough as set up by industrial fan 22.

Retention section 8, of enlarged diameter and length spirally arranged feeding ights 23 which raise and drop the material therein and urge it rather slowly toward the' discharge extremity of the drum countercurrent to the flow of cooling or heating air therethrough from neck 6. Due to the spiral flights in sections itl and S and due to the concurrent flow of the air in section l@ the axial flow of material is faster in section 10 than in retention section 8, where the air iiow opposes the axial movement of the material toward the discharge end of the unit.

Unloading pipe structure 24 is shown appropriately affixed at its lower extremity against the wall of conical section 7 and aiiixed at the outer extremity of retention section 8 of the drum, extending angularly through neck 6 of the drum and appropriately affixed outwardly thereof by means of a suitable bracket, its open discharge extremity 25 being disposed outwardly of neck 6 for the delivery of processed material. Unloading pipe 24 is shown as rectangular but may be of any desired crosssectional configuration and is appropriately 'bistd 'or openedvat its lower extremity to provide a.scoop or trough section Z6, the opening of which may be varied, to receive processed material fed to it through retention section4 ti against the flow of processing air. Unloading pipe 24 is preferably provided with a valve means-27 pivotally mounted 'in the upper, extremity of tle scop section 26 thereof and provided with alc'otrol .lever .29 which is freely accessible to the operator to adjust L't'he position of.valve A27 in .scoop section 26 to regulate .the t overflow level and amount of processed, material discharged through unloading pip'e 24. Valve 27 is shown as rectangular butmaylbe of .any.desired shapeand configuration to conform to the shape of unloading-pipe. and maybe mounted upon ashaftiorjmay be hingedly mounted within scoop section 2.6`of unloading pipe-2K4. lt will be seen that when valve'Z'lis in closed postion a small overflow section 28.0f the..scoop. section 264'will remain openabovethe valve.. Thus, whenthe valve is closed only the overow section 28 of the scoop 26,.` located above the valve, iseffective and will maintain'the material level at valve height.

AUnloading pipe 4Zis so4 designed asto,contr-,olftheh unloading of processed material from section 8 of' the coolerdryer and the scoop Vportion26..thcreof scoops up and delivers a measured portion of the material for eachrotation of the drum. ,The speed of rotation ofthe cooler-dryer unit Acontrols thegrateof feed of material to the discharge extremity ofthe unit and also governs theprate of discharge Vthrough unloadingp'ipelj. DeliveryI ofimaterial .through theimloadirrg pipe. can thus beregulated by varying `the ,Rfl ,M. of thewdrurn andY by valve 27, which can be,p ositioned to maintain ,aj desiredlevel of material irl Stiorr .8 f theA dormi.. .Valve v2.7; maytke. a variety Of-.forrrrs- .Its positionirr. pine. .24 tends tolfllstermine the'l natural'material,levelinsection 8, when closing @it the. lower-section@ th.e..0.nerr s'cqop.-

Referring; the ,fecisxtrerrrity or. breechinanf .the dryer and cooler, an appropriate sealingplatepnsealing ring 30 iS. Provided .adjacent the Orificedtextrstrrity streed Section O f. the. unitfand istprvidad with pripherally disposed flexible seal3 1 bearing out its innerextremities against the outer periphery of feedvsectionl .thereof'to provide ankairtight seal, about feed` section 110 to prevent the leakage of air` into the feed4 breeching and feed`.sec tion 10. Sealmernber 3 1 is :preferably'inthemform o fka circular seal clamped ,-at its outer peripheral extremities in a peripheral clamp32 providedabout bthe oute r periphery of sealing pl ate30. Sealing plate 3Q is preferably provided with an oif-center-circular oricek 33 ofslight- 1y larger diameter than exhaust duct 20, whih.extends therethrough and through section 110 in to conical section 9 of the dryer drum.. Circular oriiiceha is preferably provided about its peripherywith aniangle ring i34 which is appropriately clamped.thereaboutandservesI to` sillidably support extremity 44y of exhaust duct l2 10'i'nt-hel desired horizontal position within.section(10.; lalfurtherfplate andbracket support 35' is providedwoutwl rdly pf. the support bracket and is also appropriately `ri-:Iecl for `the passage of exhaust duet 2t), circulartangle member/1,36 being providedabout the peripiteigyfof `said xirifcey to further support exhaust duct4 20 adjacent its "outer 'extremity. 1,. ,Y l.

Sealing plate 30 and plate 3:5 are appropriately lmo'uiiied on a'xed base 37 and are .connected bya eircurnfereintial plate 38 joining their edges forming feed"bfreeching, Closure plate 38 is appropriately orificed for the reception and supportof material freed hutew19,whichzextends downwardly itherethrougmr itsl iopen lowerextr'ernity 09 being so disposed laterally of exhaustA duct ,20 "as tqf'eed the material tobe processed into.l section o f lthedrum to the Vside of exhaust duct` whereit willhbepicked up and moved inwardlysby spiralI fiighltlZl ofwfr'eed section 10. Asshown, material feed chute A19p is langlediatgits lower extremity inwardly., .itslorverrtrernity extending through'orice 55 in sealing plate'30 to feed the material 4 'iiit 'the outer extremity of section 10 of the dryer". Material may be fed into feed chute 19 from any suitable source and by any suitable means.

Internal exhaust duct 20, as shown, is preferably composed of a fixedly mounted cylindrical section 41 which is appropriately mounted on and communicates through the outer wall 42 of fan housing or duct 43 adjacent fan 22. Closely and slidablytted over fixed section 41 of exhaust duct'20gis slidablesection 44 thereof provided at y its outer extremity with a belled throat portion 45 in such fashinthatslidabl'e section imay be slid inwardly -or outwardly overxed section l41of exhaustjduct 20 `to regulate the length of exhaust duct '20 and the position of its'outer belled'throat`45 'withinconicalvsection 9 of the drum or within feed section 10 thereof for a purpose hereinafter to beidiscs'sedtin mre'detil.

By providing this telescoping sectional arrangement of exhaust duct 20 the discharge of fine particles of material from the drum to the conduit 43` and`cyclone separator may becontrolled and the inlet end of the cooler-dryer is kept free from: dust losses to atmosphere. 4Internal exhaust duct 20 eliminates the dust-problem by locating the areaof deepest'suctionl pressure whichf is lower than `atmospheric pressureinside theirrlet end of ythe cooler-dryer whereby the'fine vdust` is suckedfrom thecooler-dryer inlet end, into the mouth Aof the internal -exhaust4 duct"20 andthence blown or sucked toi the cyclone collector. "Ifhe heavier;particles.)are not pulled'- into the-exhaust du'ct r210 and travel on against the air s'treamh'through; the length of thecoo1erdryer Vuntil theyV arie'heldat the discharge end wheretle c'ountercurrentincorriinglair` velocity is high. Slidable section 44Hof exhaustduct 2.0`slidably fits over er into fixed section thervofdarid is so designed that theAover-all lengthof exhaust' duct 20 may beV regulated, as desired, by sliding section 44 on section 41 inwardly or outwardly.v Thus,` senction 44 may be slid'in an outward direction-toward fan 2N2 to "reduce theV length'of duct 2.0. ptrrrayle nutrirsi. '.irryy'arely. fy'rard section 8` f the dryer toincre'ase the length of duct 20. Various means rnraynbe employedito regulate the positionof-setion 44 on section 41 and the length of exhaust duct 2 0. As shown, a series of locking bolts may be provided about-the outerv periphery of section, 44, registeringagainst the outer s urfacewof fixed section 41,`l oosening of the bolts. permitting the sliding of section 44;as desired, on section 41 to regulate the length of duct 20, the' bolts being turned down into frictional engagement with the outer surflace of section41 when the desired length is'attained. To make this adjustment the cooler-dryermay be entered, or it may be made through theyfeedbreeching.

'As an alternative,` elongatefadjusting screws maybe provided extending through4 wallS of the feed breeching structure, registering with nuts provided' about the periphery of the outer extremityJ of sectionr 44'tomove section 44 inwardly or outwardly- 3onseetion 41;-as-de sired.

Exhaust duct 20 rnay be' made Ain one pieceandr ofa fixed length where desired rand Vthe best -positionisknown. The farther the bell mouth 45` of section 44 extends into conical section 9 Jof 'the uuitthe-largerfis the portion of the unit which works as a concurrent cooler or dryer and the 'smaller the sizeand amount offines which will b e sucked out through exhaust duct 20. i

Withjslidable extremity 44 moved outwardly to shorten exhaust duct 20 'to its minimum length bell mouth 45 thereof is moved into the inner extremity of feed section 10 and thus the fines do not enter section 9 of the coolerdryer but are pulled through feed sectiony 10 to bell mouth 45 of exhaust duct 20 and are then pulled rapidly through duct 20 'andi-forced up conduit 41 to the'cyclone separator. A Thus, by regulating the length of exhaust duct 2) the area of deepest suction inside the inlet endof` the cooler-dryer may be positioned, as required, andthe dust particles of a certain siz'e separated from the rest of the material and discharged from thelc'yclone. In

f conventional countercurrent coolers or dryers, not provided with such an exhaust duct, the line dust will not travel against the air in the cooler or dryer and tends to collect at the seal. This causes wear on the seal, loss of valuable fine material and a dust laden atmosphere, since the air velocities normally are not high enough to pick up the dust and carry it to the cyclone collector.

Industrial fan 22 is provided adjacent `the open terminal extremity of exhaust duct 20, rotatably mounted on a shaft 46 in the lower extremity of housing 43 of conduit 47 which extends upwardly therefrom to a cyclone collector for the 'ine particles, which is of conventional form and which is not shown. A damper 49 is preferably provided in duct 47, between fan 22 and the cyclone separator for fines to assist in the control of air flow through the unit. This damper will be located in the exhaust duct of the cyclone separator when the separato-r lies between the unit and fan 22. Fan 22 is driven from an appropriate source of power through a pulley 48 mounted at the extremity of shaft 46 and acts to pull processing air through entry section 6 of the cooler or dryer drum, through retention section 8 thereof and outwardly through the exhaust duct 20, passing through feed section l thereof. Fan 22 forces this processing air upwardly through conduit 47 to the cyclone collector wherein the fine particles of the material are collected. By controlling the speed of rotation of fan 22 or by adjusting damper 49 in duct 47 or in the cyclone exhaust duct the speed of the processing air passing through entry neck 6, retention section S and suction pipe 20 may be controlled as desired and the processing time of the material may be regulated thereby.

lf desired, the cyclone separator may be located on the clean side of fan 22, in conduit 47, between exhaust duct 20 and fan 22, thus eliminating the handling of dust or fines by fan 22, through fan housing 43. This is standard practice when handling fertilizers and many other materials.

In view of the novel configuration and arrangement of the cooler or dryer drum and the spiral flights in sections 10 and 8 thereof the material being processed is picked up and showered from the flights and is moved toward the discharge extremity 6 of the drum countercurrent to the flow of processing air pulled therethrough by the fan 22. The spirally arranged flights have an inclination designed to feed the material and move it countercurrent to the air ow thus allowing more air to be used and increasing the eiciency of the processing of the material and giving a greater capacity for size.

The time of retention of the processed material in section 8 of the drum may be accurately controlled through the valve 27 of the unloading pipe 24, the open scoop section 26 of which is disposed adjacent the terminal extremity of retention section 8 of the drum. It may also be controlled by regulating the R. P. M. of the drum or by regulating the rate of air flow.

If it is desired to use the structure as a countercurrent heater and dryer an appropriate source of heat may be provided adjacent the neck 6 of the dryer to heat the processing air to the desired temperature as it is pulled into neck 6 by fan 22. Conversely, if it is desired to cool the processing air appropriate cooling means may be provided. v

Feed section llt) may be supplied with hot, dry air through an orifice 53 in casing 38 and orifice 55 in plate 30, thus furnishing the concurrent air to the feed section 1t) in the form of dry, hot air, the cooling air stil entering through section 6 and flowing countercurrently. The breeching, consisting of the seal plate 30, plate 35, and casing 38, in such case may be insulated with refractories or other insulating material.

As shown in Fig. 2, orifice 55 in seal plate 30 is preferably disposed therein about the exhaust duct 21) and is curved in configuration in roughly a half moon shape, about duct Ztl. It is preferably of a width at its widest asados-i hot air furnace supplying duct 56. The main exhaust fan 22 together with the main exhaust damper 49 will still determine the total amount of air being handled and balance it to requirements.

Such a unit will act as a combination dryer-cooler and when wet material enters through feed chute 19 and drops into feed section 10 it will be immediately engulfed in the concurrent ow of hot air owing through duct 56, orifice 53 and curved orifice 5S in plate 30. The surface moisture is thus quickly evaporated and while the material moves concurrently with the air flow through section 10 toward decreasing temperatures it is gradually heated while the gases cool down. The hot gases and vapors are then sucked off through exhaust duct 20 before they can enter retention section 8. The material, however, moves countercurrently against the increasingly cooler air flowing against it, while being cooled both by the cool air and by evaporation. Finally the material is discharged dry and cool through unloading pipe 24.

When operated in this manner the unit performs both the concurrent drying and heating operation, which normally is performed in a separate concurent dryer, and also the countercurrent cooling operation, normally performed in a separate countercurrent cooler. Since for temperature sensitive materials concurrent drying usually yields the greatest capacity for a given size dryer and since a countercurrent cooler yields the greatest capacity for a given cooler size, this combination of a concurrent dryer plus a countercurrent cooler provides in one unit the ideal and most compact solution to many drying and cooling problems. Where both operations can be satisfactorily performed in one single unit it is obvious that great savings in cost and space requirement, as well as in maintenance can be expected.

The operation of the countercurrent cooler and dryer is broadly as follows. With fan 22 rotating and with the drum under rotation through ring gear 17, air flow and speed of rotation being as desired, the material to be processed is fed through material feed chute 19 into feed neck 10 of the drum structure. In feed section l@ the material is raised and dropped and moved forwardly toward retention section 8 by means of spiral flight 21 and the inward air flow through section 10 until the bulk of the material is moved through conical section 9 into enlarged retention section 8. In section 8 the material is raised and showered and progressively moved toward the discharge end thereof by means of spiral flights 23 against the flow of air therethrough, the processed material finally reaching the scoop extremity 26 of unloading pipe 24. The time of retention of the material in retention section 8 may be accurately controlled to assure the desired period of treatment. This control may be had by controlling the speed of air flow, the speed of rotation of the drum and by controlling the extent of opening of the valve 27 of unloading pipe 24 at the extremity of section 8 of the drum. If it is desired to retain all of the processed material for an extended period in section 8 of the drum valve 27 may be maintained for an extended period in closed position. cyclic operation.)

As neck section 6 and exhaust duct 2i) are of reduced diameter air velocity through these two terminal sections is high. Thus processing air enters through section 6 at high velocity. Its velocity is progressively reduced thro-ugh conical section 7 and air velocity is at its lowest passing through enlarged diameter retention section 8. Air velocity again progressively increases through de- (Batch or creasing conical section 9 into exhaust duct 20 where air velocity is at its highest. -Thus, by adjusting the inner telescoping section-44'of'exhaust duct 2.0 over or within the fixed section"41`- thereof the bell mouthf45 thereof may be moved inwardly into'feedsection 10. As the velocity of air passing through duct L2040 fan 22 is preferably S-6000 F. l. M., which is -a conveying velocity, and the air` flow through feed sectionltlis inward to bell mouth 45, fine material willfbe pickedup in section 10, cooled and/or dried andpulled directlythrough duct 20 and conduit '47 `tothe cyclone collector, leaving the coarser' material to pass`tlirough`sections9 and 8 of the drum for processing therein and discharge therefrom through dischargepipefZ. TByvirtue ofthe high velocity of the processing air'passingthroughentryneck of the drum none' of the processedmate'rial will escape through neck 6, its Yforward `move'mentlinduced by spiral flights 23 in retention sectiont of the "drumbeing positively opposed by the high lvelocity `air 'entering through neck 'sectionfthereof c Due to the provision `of'internal exhaust duct '20, passingthroughrbreeching-plate 30into the retention section 8 of the unit the air ilow through feed section 10 moves in concurrent flow Wi'ththe material and thus assists inmoving the matcrialinto the retention section8 from feed section 1t). The only air passing through feed section10 is the airfsucked or pulled through'the feed chute 19 or passing through opening'S, provided in breeching plate "38 from hot air duct 56. Thus even the finest materi-al will have no 1tendency to escape through the seal as it would thus be inopposition to air movement in section 10.

Whereit is particularly/important to separate the tine from the coarser Jmaterial -the `inner extremity V44 of suction-pipe '20 may ibe retracted on'section -41 thereof into feed 'section 1`0 oftthe drum'so that it will pickup the 'fine materialiin 4feed-"section llllandseparate it from the coarser material. 4Such a-separation of the fnematerial islfrequen'tly desirable, for example, 'in the fertilizer industry where it is "iimportantnot to overload screening equipment and `wherethe"ines can ybebloWn by the fan to the cycloneand readily recovered therein.

It will thus be seen -that in the present countercurrent cooler and dryer `structure a machine ofgreat capacity for'unit size has been provided in which the tine material may `be readily separated 'atthe feed end from the coarser materialand inf-which the coarser material may be processed in the'retention section for the desired period 4while being fed countercurrent to the-processing air stream. By providing the extensive Vspiral flights 23 intretention section-8 the material is V"heavily showered therein and is actedupon by'the countercurrent owing air while being steadily moved toward the discharge end -of the retention `section. The ultimate processing time control in this -structure is; governed bytheamount of air regulatedby fan"22 and damper v49, .the speed of rotation and by the u'nloa'dingpipe24 and valve'27regulating the timeof retention'of `the material insection'S and the delivery of processed material therefrom.

This cooler-dryer-structure is susceptible to many uses and adaptable to the 'processing of many diierent'types of material. It canbeused as "a countercurrent cooler, countercurrent fdryer or as a fcombination concurrent dryer countercurrentcooler or'asa mixer` or reactor for various typesof material. 'Nothing inthis specification is intended'to' limit the scope ofthe invention and throughout'the substitution 'of Yanalogous elements may be made without 4'departing from the spirit of thisinvention.

Attention is directed .to the appended claims for a limitation of the scope-offthis invention.

AWhat is claimed is:

1."In a countercurrent-coolerrand dryer for material, a rotary drumcomprising a\ cylindrical air entry neck of small diameterfa divergent, conical.V section adjacentwsaid entry neck, a retention section of enlarged diameter and length adjacent to'fandextending from said conical section, v'-a convergent conicalsection adjacent said retention sectionextending-nto alfeed section of reduced diameter andleng`th,said sectionsfbeing disposed onthe same longitudinalaxisga seal lplaterclosing the extremity of said feed section, a-materialifeedrduct extending into said feed section, alhotfair-ducteornmunicating with said feed section, `an t exhaust duct lof Areduced diameter disposed through-fsaid feedsectionand Said seal plate and eccentric therewith, a`fanin1sealed communication with the extremity of `said exhaustduct, a duct leading from said fan to a.eyclonetcolleetorl-forne material, spiral flights in saidfeedtand retention-sections and an unloading pipe extending from the -extremity=of said retention section through saidfentry .neck-whereby'processed material will be delivered from Vsaid retentionsection through said unloading pipe.

l2.In a countereurrent Lcooleranddryer for material, a rotary-drumreomprising a cylindrical entry neck of small ldiameter, :a divergent conical section adjacent said entry neck,-a retention sectionrof enlarged diameter and length `fadjacentetoiandxtending from said conical section,` a convergent conicalsection adjacent said retention section extending into-a feed section of reduced diameter and length,'saidrsectionsbeing disposed on the samelongitudinalfaxis, a=seal.plate .closing the extremity of said feedfsection, afmaterial feed duct extending into saidfeed'sectiongahot air duct .communicating with said feed section, -a telescoping exhaust duct of small diameter disposedthrough saidifeedsection and said seal plate and 'eccentriottherewith al fan in sealed communication with the extremity of `said.exhaustduch a duct leading from saidfan to ,fa1cyclone:.collectorfor fine material, spinalflights insaidtfeedf'and `retentionlsections and -an unloading tpi-peiexitending fromthe .extremity of said retention section-.through` said entry neck wherebyprocessedimaterial'wilhbe delivered from4 said retention section through said unloading pipe.

V3. I'nfa'tcountercurrentcooler and dryer for material, a rotary-.drum comprising `acylindrical entry neck of small diameter, a ,divergent conical section adjacent said entryuneck, `axretention section of ,enlarged diameter and length 4adjacent to-and Aextending from said conical section, aiconvergent conical' sectionv adjacent said retention section extending `in to'a :feed :section of reduced diameter and 'lengthfsaid sectionsibeingdisposed on the Same longitudinal-axis, a'seal plate closing the extremity of said feed section, a .lmaterialfeedrduct extending into said feed section,a-hotairduct communicating with said feed section, Aa longitudinally:extensible'exhaust duct extendingzthroughisaidfeed section `toward said retention section, a fan insealedlcommunication with the extremity of said,exhaustduct, a duct leading from said fan to a cyclone collector for wfine material, spiral flights in ,said feed I*and retention sections and -an unloading pipe` extending from .the nextremityvof said -retention section throughfsaid entry neck' whereby processed material will be delivered from said retention'section through said unloading pipe.

4. rInfa countercurrentcooler and dryer for material, a rotary drum comprisng-a lcylindrical entry neck of small diameter, awdivergent conical section adjacent-said entry neck, a retention section of enlarged diameter and length -adjacentrto and extendingffrom said conical section,.aconvergent conical section'adjacent said retention section'` extending' into -az lfeed-section of reduced diameter and length,:said` sections being, disposed on the same longitudinal1axis,aseal plateA closingthe extremity of said feed section, amaterial feed duct open atfits upper vextremity extending intosaid feed'section, a hot air duct communicating with said feed section, a longitudinally extensible exhaust duct extending through said feed section, a fan in sealedcommunicationwith the` extremity of said 'exhaustduch -a-=cluctA leading; from; said. fan to` a,

ascissa',

cyclone collector for iine material, spiral flights in said feed and retention sections and an unloading pipe extending from the extremity of said retention section through said entry neck whereby processed material will be delivered from said retention section through said unloading pipe.

5. In a countercurrent cooler and dryer for material, a rotary drum comprising a cylindrical entry neck of small diameter, a divergent conical section adjacent said entry neck, a retention section of enlarged diameter and length adjacent to and extending from said conical section, a convergent conical section adjacent said retention section extending into a feed section of reduced diameter and length, said sections being disposed on the same longitudinal axis, a seal plate closing the extremity of said feed section, an angular material feed duct extending into said feed section, a hot air duct communicating with said feed section, a longitudinally extensible exhaust duct extending through said feed section into said retention section, a fan in sealed communication with the extremity of said exhaust duct, a duct leading from said fan to a cyclonecollector for tine material, spiral iiights peripherally disposed in said feed and retention sections and a valved unloading pipe extending from the extremity of said retention section through said entry neck whereby processed material will be delivered from said retention section through said unloading pipe.

6. In a countercurrent cooler and dryer for material, a rotary drum comprising a cylindrical entry neck of small diameter, a divergent conical section adjacent said entry neck, a retention section o-f enlarged diameter and length adjacent to and extending from said conical section, a convergent conical section adjacent said retention section extending into a feed section of reduced diameter and length, said sections being disposed on the same longitudinal axis, a seal plate closing the extremity of said feed section, an open material feed duct extending into said feed section, a hot air duct communicating with said feed section, a longitudinally extensible exhaust duct of reduced diameter extending through said feed section into said retention section, a fan in sealed communication with the extremity of said exhaust duct, a duct leading from said fan to a cyclone collector for ne material, high spiral flights arranged within said feed and retention sections and a cylindrical unloading pipe extending from the extremity of said retention section through said entry neck, a scoop at the inner extremity of said unloading pipe whereby processed material will be delivered from said retention section through said unloading pipe.

7. In a countercurrent cooler and dryer for material, a rotary drum comprising a cylindrical entry neck of small diameter, a divergent conical section adjacent said entry neck, a retention section of enlarged diameter and length adjacent to and extending from said conical section, a convergent conical section adjacent said retention section extending into a feed section of reduced diameter and length, said sections being disposed on the same longitudinal axis, a seal plate closing the extremity of said feed section, a vertically disposed, open material feed duct extending into said feed section, a hot air duct com-l municating with said feed section, an exhaust duct of reduced diameter disposed through said feed section and said seal plate and eccentric therewith, a fan in sealed comunication with the extremity of said exhaust duct, a duct leading from said fan to a cyclone collector for fine material, steeply angled spiral flights in said feed section, more gradually angled spiral flights in said retention section and an open-ended unloading pipe extending from the extremity of said retention section through said entry neck whereby processed material will be delivered from said retention section through said unloading pipe.

8. In a countercurrent cooler and dryer for material, a rotary drum comprising a cylindrical entry neck of small diameter, a divergent conical section adjacent said entry neck, a retention section of enlarged diameter and.

length adjacent to and extending from said conical sec# tion, a convergent conical section adjacent said retention section extending into a feed section of reduced diameter and length, said sections being disposed on the same longitudinal axis, a seal plate closing the extremity of said feed section, an angular material feed duct extending into said feed section, a hot air duct communicating with said feed section, an exhaust duct of reduced diameter disposed through said feed section and said seal plate, a fan in sealed communication with the extremity of said exhaust duct, a duct leading from said fan to a cyclone collector for ne material, spiral flights ink said feed and retention sections and a valved unloading pipe extending from the extremity of said retention section through said entry neck whereby processed material will be delivered from said retention section through said unloading pipe.

9. In a countercurrent cooler and dryer for material, a rotary drum comprising a cylindrical entry neck of small diameter, a divergent conical section adjacent said entry neck, a retention section of substantially twice the diameter and three ,times the length of said entry neck adjacent to and extending from said conical section, a convergent conical section adjacent said retention section extending into a feed section of reduced diameter and length, said sections being disposed on the same longitudinal axis, a seal plate closing the extremity of said feed section, an open material feed duct extending into said feed section, a hot air duct communicating with said feed section, an -exhaust duct of reduced diameter dis posed through said feed section and said seal plate, a fan in sealed communication with the extremity of said exhaust duct, a duct leading from said fan to a cyclone collector fory fine material, spiral flights in said feed and retention sections, an open-ended unloading pipe extending from` the extremity of said retention section through said entry neck, a valve in said unloading pipe adjacent its inner extremity whereby processed material will be delivered from said retention section through said unloading pipe.

10. In a combination concurrent dryer and countercurrent` cooler for material, a rot-ary drum comprising a cylindrical cool air entry neck of small diameter, a divergent conical section adjacent said cool air entry neck, :a retention section of enlarged diameter and length adjacent to and extending from said conical section, a convergent conical section adjacent said retention section extending into a feed section of reduced diameter, said sections being disposed on the same longitudinal axis, a seal plate closing the extremity of said feed section, a feed casing integral with said seal plate, a material feed duct extending into said feed section through said feed casing, an exhaust duct of reduced diameter disposed through said feed casing and said seal plate into said feed section, an orice in said seal plate, a not air duct communicating with said feed casing, a fan in sealed communication with the extremity of said exhaust duct and communicating with a cyclone separator and an unloading pipe extending from the extremity of said retention section through said entry neck, whereby processed material will be delivered from said retention section through said unloading pipe.

l1. In a combination concurrent dryer and countercurrent cooler for material, a rotary drum comprising a cylindrical cool air entry neck of small diameter, a divergent conical section adjacent said cool air entry neck, a retention section of enlarged diameter and length adjacent to and extending from said conical section, a convergent conical section adjacent said retention section extending into a feed section of reduced diameter, said sections being disposed on the same longitudinal axis, a seal plate closing the extremity of said feed section, a feed casing integral with said seal plate, a material feed duct extending into said feed section through said feed casing, an exhaust duct of reduced diameter disposed through said feed casing and said seal plate into said feedsection, an enlarged, curved oritice in saidrseal plate, `avhot air-duct communicating with said feed casing,a Vfan in sealed communication with the-extremity kof` said exhaust ductiand` communicating witha cyclone separator and an `unloadingupipe extending from the ,extremity of said retention section through' said entry` neck, whereby- Aprocessed .materiahwillbefdelivered fromrsaid yretentionrsection throughsaid unloading #pipe l2.1In1 a combination concurrent dryer andccountercurrent cooler -formmateriaL -a rotary drum comprisingfa cylindrical cool air-entry necks of small diameter, a divergent conicalsection adjacent said cool air entry neck, a retention V4section of 4enlarged diameter=and"length adjacent-toand extending `from said conicalsection, a convergentconical section adjacent said retention section extendinginto a` -feed section of reduced diameter, said sections being disposed on. the same llongitudinal axis, a seal plate closing the'extremity of said feed section, -a feed casing integralwith said seal\plate, a material feed ductextending into said -feed section through said `feed casing, -an exhaustduct of reduced diameterdisposed throughsaid feed casing and said seal plate into said feed section,an oriicein said seal plate curved about said exhaust duct, a hotairduct communicating with said-feed casing, a fanin sealed communication with theextremity of said exhaust duct and communicating with a cyclone `separator and an unloading pipe extending from the extremity of said retention section through said entry neck, wherebyprocessedmaterial will be delivered-'from said retention section through said unloading-pipe.

13. In a combination `concurrent dryerand-countercurrent cooler for material,a rotary drum comprising a cylindrical cool air entry neck of small diameter, aV divergent conical sectionadjacent said cool air entry'neck, a retention section of enlarged diameter and length adjacent-to and extending from said conical section,`acon vergent conical section adjacent said retention section extending into a feed section of reduced diameter, said sections Ibeingdisposed on the same llongitudinal axis, a seal plate closing the extremity of said feed section, a feedcasing integral with said Aseal plate, a material'feed duct extending into said feed section through `said feed casing, an exhaust duct of reduced diameterjdisposed through said feed casing andA said seal plate into said feed section, an orifice of substantial size `in s aid `seal plate, a hot air 4duct communicating with said feed casing, a fan in sealed communication with the extremity of said exhaust duct and communicating with a cyclone separator and an unloading pipe extendingv from the extremity of said retention section through said entry neck, whereby processed material will be delivered from said retention section through said unloading pipe.

14. In a combination concurrent dryer and countercurrent cooler for material, a rotary drum `comprisinga cylindricaltcool air entry neck of small diameter,'adivergent conical section adjacent said cool air r entry'vneck, aretention section of enlarged diameter Aand length adjacent to and extending from said conical section, a convergent conical section adjacent said retentionsection -extending-into afeed section of reduced diameter, Asaid sections being :disposed on the same longitudinal axis, 'aseal plate-closinglthe extremity of said feed section, *alfeed casinglintegralwith said seal'plate, a material feed duct extending into said feed section through said fee'dcasing, anexhaust duct of reduced diameter disposedthrough sad'gfeed casing and said seal plate into said feedesection, an Aorifice in said seal plate, a` hot air duct communicating Awith said-feed casing, a valve in saidhot airlduct, a fanin sealed communication with the .extremity of said exhaust duct Vand communicating with a cyclone-separator and an unloading pipe extending from'the'extremity of said retention section through said entry neck, whereby processed material will be delivered from said retention section throughsaid unloading pipe.

1,5.In a combination concurrent dryer and countercurrent cooler for material, a rotarydrumcornprising a cylindrical cool air entry neck of small diameter, adivergent conical section adjacent said cool air entry neck, a'retention section of enlarged diameter and length .adjacent to and extending from said conical section, a convergeut conical section adjacent said retention section extending into a feed section of reduced diameter, .said sections being disposed `on the same .longitudinal axis, ,ai seal` plate closing the extremity of said feed section,.a feed casing integral with said seal plate, a material feed d uct extending into said feed section throughsaidfeed casing,'an exhaust duct of reduced diameter disposed through said feed casing and said seal plate` intol saidl feed section, an orice in said seal plate disposed about said exhaust duct, ahot air duct communicating `with said feed casing, a fan in sealed communication with the extremity of said exhaust duct and communicating with a cyclone separator and an unloading pipe extending `from the extremity of said retention section through said entry neck, whereby processed material will lbe` delivered from said retention section through said ,unloading pipe.

References Cited in the file of this patent UNITED STATES PATENTS 1,293,780 Hornsey Feb. 11, 1919 `2,069,164 Vogel-Jorgensen Jan. 26, 1937 2,470,315 McGehee May 17, 1949 21,504,714 McGehee Apr. 18, 1950 

